Biometric identification process and system utilizing multiple parameters scans for reduction of false negatives

ABSTRACT

A system for verifying that a card possessor is the authorized card owner compares scanned fingerprint data with fingerprint data encoded on an optical card. More than one of the person&#39;s fingerprints are encoded on the card, and the process of identification of the card possessor involves the random selection of separate fingerprints for scanning and comparison against the encoded fingerprints. A card reader/writer reads fingerprint characteristic information from an optical card inserted therein and a processing unit, connected to a fingerprint scanner and card reader/writer extracts from the scanned fingerprint certain well known indicators, and matches the recorded fingerprint characteristic data with the scanned fingerprint characteristics to establish identity therebetween.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of application Ser. No.08/523,328, filed Sep. 5, 1995 now abandoned.

BACKGROUND OF THE INVENTION FIELD OF THE INVENTION

The present invention is generally related to a method and system forverifying the identity of a person, notably by comparing certainphysical characteristics of the person, in one embodiment, thefingerprint of the person, with a recorded copy of informationcorresponding to the characteristics of that person provided on anoptical card. In the present invention, the process of verifying theidentity of the individual card owner involves the successive andsequential comparisons of one or more single characteristics, e.g.,fingerprints, preferably randomly selected if more than one is requiredto verify the identity. This method of proceeding facilitates anidentification of the individual while maintaining a higher degree ofaccuracy due to the possible use of higher degrees of correlation thatthose that are normally available when matching a single physicalcharacteristic.

BACKGROUND OF THE INVENTION

Currently, bank cards are used throughout the world which comprise oneof more magnetic strips or other recording medium on or in the card,carrying coded information thereon. Although simple to use, there is noinherent means in the card for verifying that the person presenting thecard is actually the true owner of the card. While in many circumstancesa user, will input a Personal Identification Number (PIN) into a bankcard machine, the level of security afforded is still not high, giventhat many users will write down a PIN number in a check book or thelike, making the number easily accessible to a criminal.

There are other circumstances in which a verification of the identity ofpersons is necessary. Debit and Point-of-Sale cards are gaining the samepopularity as credit cards. Welfare systems are investigating automaticdistribution of benefits through a carded system. When businessmentravel between countries it is necessary to verify the identify of eachperson passing through customs and identify each as citizen, residentalien, permanent resident and the like. The identification must beaccurate, but not too rigorous to be inconvenient. There are a number ofpossibilities for biometric identification including physical features,hand geometry, retinal scans, facial images, fingerprints and the like.

It has been proposed by many that the minute details of a person'sfingerprint could be encoded (i.e., in binary coded form) into memory ona card. For example, a coded version of a fingerprint can be stored upona card. When verification is required, it is necessary for the user todisplay his fingerprint to a scanner, and at the same time insert a cardinto a reader which extracts the coded information identifying thefingerprint, and with a processor, compare the authorized owner'sfingerprint with the stored characteristics of the owner's fingerprint.

However, the accuracy of such systems is limited, since normally thesesystems only record some of the characteristics of a person'sfingerprint on the card. And the environmental measurement conditionsand positions must be matched as well. False rejections are very commonon the single fingerprint identification systems. A rotated or rolledfingerprint, fingerprints taken or scanned with different pressures ofthe finger on the scanner while it is being scanned initially, dirt, ablemish or other injury on the finger being scanned, all are potentialproblems leading to false rejections. While conserving memoryrequirements, the accuracy of such methods, using only a singlefingerprint, can be very low. The comparison of a single scanned fingerwith the corresponding recorded fingerprint information thereto, mayincorrectly provide false rejections due to any of these conditions. Forexample, these systems do not account for temporal perturbations, e.g.,a scraped, burned or cut finger, that may exist on the owner's finger,thereby giving rise to a false reading of the single fingerprint image.

The need to verify with accuracy the identity of a card owner isnecessary in a wide variety of circumstances, including at a passportand immigration check, at banking and other financial systems, highsecurity areas and the like. What is needed is a method making it moredifficult for criminals to fraudulently use a stolen card and the like.As more and more accuracy is required the probability of falserejections increases. The need for a simple, more accurate method whichfacilitates the verification process is thus of increasing importance.

SUMMARY OF THE INVENTION

Accordingly, the present invention provides a method and system forverifying identification of a person with increased accuracy, whileconcomitantly, reducing the probability of false rejection for theauthorized card owner.

The method includes the steps of comparing a scanned physicalcharacteristic, such as a fingerprint, with recorded informationcorresponding to the scanned physical characteristic, e.g., afingerprint, as known in the art, but goes beyond the state of the artby using a novel process of randomly and sequentially selecting morethan one physical characteristic for scanning and comparison againstrecorded characteristic data, thus enhancing the accuracy of theindividual identification process and reducing the probability ofimproper false rejections.

In this manner the invention can be used for persons temporarilydisabled due to broken bones or to sprained muscles, paraplegic persons,persons who cannot provide a certain finger for scanning due to a recentaccident, for example, or victims of intentional maiming or accidentswho no longer possess a hand or have lost fingers. Furthermore, theinvention accounts for a poor scan, resulting in an improper falserejection, for example, on a single fingerprint, or rejections due toinjuries or to dirt or blemishes on the selected finger or the scanningequipment. The invention advantageously reduces the number of falserejections while at the same time enabling the use of a high comparisoncorrelation to ensure a low number of false acceptances.

The system utilized by the method of the invention includes a storagemedium, preferably portable, and more preferably an optical card,storing more than one characteristic, e.g., fingerprint, of theauthorized card owner, a device for reading the stored characteristics,preferably a card reader/writer into which the card is inserted, orplaced thereon, and which accesses the recorded characteristic data ofthe card owner, a scanner (reading means) for reading a selectedphysical characteristic, e.g., fingerprint of the card owner, and aProcessing Unit (PU) for extracting essential characteristics of thescanned body part and comparing these characteristics with the recordedphysical characteristics.

Potential applications of the invention include, for example,controlling entry at passport and immigration checkpoints, ensuringpersonal identification in financial transactions (e.g., credit cardsystems), and enhancing security at high security installations, and thelike.

Therefore, it is an object of the present invention to provide a methodthat increases the accuracy of the security identification through theuse of higher degrees of correlation.

It is another object of the invention to facilitate verification ofidentity by decreasing the probability of false rejections in theidentification process of an authorized card owner, while not permittingunlawful use in attempting to circumvent personal data protection.

Another object of the invention is to provide an individual recognitionsystem comprising: a storage medium storing as biometric data aplurality of physical characteristics of a user; reading means forextracting from the user biometric data representing one of the physicalcharacteristics stored by the storage means; comparison means fordetermining whether or not the extracted biometric data represents thesame physical characteristic as corresponding stored biometric dataobtained from the storage medium; and control means for instructing thereading means to extract from the user additional biometric datarepresenting a different physical characteristic stored by the storagemeans, depending on the determination by said comparison means.

Yet another object of the invention is to provide a personalidentification method using a data storage medium containing previouslystored biometric data representing a plurality of physicalcharacteristics of a user, the method comprising: extracting from theuser biometric data representing one of the physical characteristicsstored by the storage medium; determining whether or not the extractedbiometric data represents the same physical characteristics ascorresponding stored biometric data obtained from the storage medium;and extracting from the user additional biometric data representing adifferent physical characteristic stored in the storage medium dependingon the determination at the determining step.

Still another object of the invention is to provide an individualrecognition system for use with a storage medium on which biometric datacorresponding to a plurality of physical characteristics of the user hasbeen stored, the system comprising: reading means for extracting fromthe user biometric data representing one of the physical characteristicsstored by the storage means; comparison means for determining whether ornot the extracted biometric data represents the same physicalcharacteristic as corresponding stored biometric data obtained from thestorage medium; and control means for instructing the reading means toextract from the user additional biometric data representing a differentphysical characteristic stored by the storage medium, depending on thedetermination by the comparison means.

Other objects and features of the present invention will be apparentfrom the following detailed description in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the system components for a preferred embodiment forcarrying out the method of the invention.

FIG. 2 represents the main stages of the method according to theinvention in the form of a flowchart.

FIG. 3 provides an example of the information, including a physicalrepresentation of the user's fingerprint, that might be printed on thefront of the user's card, the reverse of which carries the codedfingerprint data as shown in FIG. 1.

FIG. 4 demonstrates the instructions to place the randomly selectedfinger and the Live Image Preview which might be obtained by the userfollowing the instruction.

FIG. 5 shows the resulting information which can be downloaded to thescanning station when the user's identity has been verified that can bedisplayed on the host CPU at a passport or immigration entry point.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 shows an embodiment of a fingerprint identification system 20 forcarrying out the method of the present invention. Using the system 20 ofFIG. 1, the fingerprints of the card owner 23 are stored on the encodedportion of an optical card 25, as part of individual identificationinformation. As shown in FIG. 3, the identity card 25 can also containother various biometric and representative information about theindividual card owner 23, recorded physically on the face of the card,as at reference numeral 28 of FIG. 5, or encoded thereon, as atreference numeral 29 of FIG. 5, or recorded on electronic or opticalmedia 30 of FIG. 1, including, for example, name, account number, dateof birth, sex, height, weight, information on citizenship, healthinspection or health information and the like might be maintained. Theoptical card 25 also comprises memory 30 shown in FIG. 1 for storing thefingerprint data. Preferably, only certain characteristics of aplurality of fingerprints are stored on the card 25, thereby conservingmemory space. The memory capacity can be reduced down to only about 1Kbyte per fingerprint when only certain key characteristic features areencoded. Such fingerprint characteristics are preferably limited to afew significant features such as the depth and interval of thefingerprint, ridge pattern information, or key features relating to thenumber and kind of vortices, arcs, crossings and other line forms shownby the fingerprints. However, it should be noted that optical cards witha large memory capacity are available, but it may be advisable for otherreasons to limit the amount of data recorded therein (for example,correlation thereof would require the processing unit used with thepresent system to have excessive computational capacity). Extraction andmatching software libraries (not shown) can be used of the typedeveloped by The Phoenix Group, Inc. of Pittsburg, Kans. However, thepresent invention works well with any fingerprint matching system.

In the present invention, data representing the characteristic featuresof a plurality of fingerprints, which may be all of the fingerprints oronly a limited number of fingerprints from each hand of an authorizedperson, are preferably coded and stored on the card 25, in the form of abinary or multi-value coded signal. This is preferably done by scanningdesignated fingers of the person when issuing a card 25 on similarequipment 20 to that which will be used during verification. Any numberof fingerprints may be chosen for scanning from one to all five fingerson each hand. Therefore, the card 25 storage mechanism 30 carriesinformation relating to more than one finger of the person 23, asexplained more fully below, so that the system can request alternativefingerprint information if one of more of the fingers are either notavailable of scanning, due to cuts, blemishes or other injury, or adefective fingerprint was originally taken or if a first or later scansfail to confirm the identify of the card holder.

Although the disclosed preferred embodiment has been described asutilizing fingerprint data, any biometric data representing a pluralityof physical characteristics can be utilized. For example, retinal scansof both of a cardholder's eyes can be encoded onto the card. Similarly,palm prints of each of the cardholder's hands can also be used. In fact,the present invention is not limited to such obvious groupings ofphysical characteristics. For example, the left hand print, right eyeretinal scan, and right hand fingerprints can all be stored on theoptical card and randomly selected ones of the body parts correspondingto such characteristics required to be presented for verification.Biometric data representing other physical characteristics, such as thecardholder's signature (its appearance or characteristics of how thecardholder forms his signature), facial characteristics, or keyboarddynamics (such as keying pressure, rate, sequence, or the like) can alsobe compared.

The remaining components of FIG. 1, namely those designate by referencenumerals 35, 37, 42, 45 will be described in relation to the flowchart,as depicted in FIG. 2, showing the main steps when using the invention.The process of identification of the individual card owner 23 with thecurrent invention is based upon the random measurement of successive andsequential single fingerprints, as opposed to the measurement of allfingerprints or merely the measurement of only a single fingerprint.

The process 45 strikes an acceptable balance between confirmation of theidentity of the card holder 23 (a low number of false acceptances) witha facilitation or ease of use of the system 20 (a low number of falserejections). The balance is achieved with two basic components.Facilitation is achieved by the use of multiple (random) fingerprintcomparisons. Therefore, if a problem, environmental or physical, impedesa first match, other fingers can be called for and scanned until a matchis achieved. Thus a high correlation of fingerprint attributes can berequired for a match, increasing the accuracy of the verification of theidentity of the user. The random nature of requests for specific fingerson either or both hands further impedes criminal activity. Finally,preferably, after a predetermined number of attempts, a decision can bemade to terminate the process with a rejection. The fact that arejection occurs only after a predetermined number of unsuccessfulcomparisons advantageously results in a minimum of false rejections,while also allowing each individual comparison to utilize a highcomparison correlation so that security is maximized.

Referring to the flow chart in FIG. 2, to initiate 62 the process 45,the owner 23 inserts a card 25 into a card reader/writer 45. Preferably,either by a display 42 or some other means, the card owner is alsorequested 64 to place one of his or her fingers on the fingerprintscanner 35. In this instance, the particular hand and associated fingerrequested for scanning is random, as the result of any conventionalrandom algorithm. The fingerprint scanner 35 can be any of a wide rangeof suitable scanners, such as those manufactured by Digital Biometrics,Inc. The scanner 35 comprises a fingerpress having a transparent sectionthrough which the fingerprint image can be obtained.

The scanner 35 reads an image 65, as shown in FIG. 4, of the selectedfingerprint of the user 66. Similar to the process of encoding thefingerprint characteristic data onto the card 25, described above, thescanning can be carried out using a number of techniques, e.g.,optically using high intensity illumination and an array ofphotosensitive diodes as a camera to record an image, or some otheroptical scanning device such as a laser scanner, to provide an imagewhich can be processed electronically.

The fingerprint pattern is converted to an electric signal 69 and sentto a peripheral PU 37 or to a PU 37 in the scanner 35 itself. In thepreferred embodiment, the extraction and matching programs are stored inthe memory of PU 37. Therefore, the fingerprint is transformed into anelectronic signal which is coded into a binary or multi-value codedsignal. Thereafter, certain characteristic patterns are extracted 75preferably using the same extraction program as that used to encode thefingerprints. The extracted characteristics preferably correspond tothose encoded onto the optical card. As mentioned above, with referenceto the card encoding process, such fingerprint characteristics arepreferably significant features such as the depth and interval of thefingerprint, ridge pattern information, or key features relating to thenumber and kind of vortices, arcs, crossings and other line forms shownby the fingerprints. The characteristic extracted are used by thematching program for comparison with the fingerprint characteristic dataencoded in the optical card.

As shown in FIG. 2, the recorded data of the particular scannedfingerprint is accessed 78 from the optical card using an optical cardreader 45 such as the RW-20 Reader/Writer manufactured by Canon Inc. ofJapan. The card reader/writer 45 receives the recorded fingerprintcharacteristic information on the card owner corresponding to thescanned fingerprint. The card reader/writer 45 outputs the recordedfingerprint information to the PU 37. The PU 37 can display the scannedfingerprint 65, along with the directive 51 indicating which finger isto be/has been scanned, as shown in FIG. 4.

The next step is the comparison of the recorded fingerprint data withthe specific extracted characteristics from the scanned fingerprintusing the matching program 82. The extraction and matching algorithmsare preferably implemented into software stored by the PU 37. Thecomparison of the recorded data with the scanned fingerprint informationcan be made according to any of the conventional matching algorithmsdepending primarily on the characteristic features extracted from thefingerprint image.

If a predetermined correlation exists between the recorded fingerprintcharacteristic data and the scanned fingerprint extractedcharacteristics at 92, a display associated with the PU 37 can eitherindicate the identification confirmation as by 101 of FIG. 4, oralternatively, a decision signal can be sent at 125 from the PU 37 to anoperational device (not shown) such as a door or gate for securitysituations, coded lights can flash or the result can be displayed on oneor more screens. The decisional pass/fail signal at 125 may also betransmitted back to the card reader/writer 45 to retain the card at 78in a failure to identify situation or optically or otherwise mark thecard at 78 to indicate border crossings, access to secured areas orother encoded records on the card at 78. A remotely located display (notshown) may also indicate that a match has been found, and therebyconfirm identification. Instead of indicating confirmation on a display,of course, the verification decision can also be indicated throughillumination of a specified color of light or other expedient, such asthe opening of a door or gate.

However, if no match has been found, at 110, instead of immediatelydenying entrance or access to or identification of the individual, asthe case may be, the present invention allows for the successive andsequential placement of further fingers onto the fingerprint scanner115. Therefore, by allowing for comparison of two or more fingerprints,the possibility of a defective signal based on an obscured orunavailable fingerprint, environmental factors, such as excess moistureon the fingers, or any artifact preventing a match from being made, canbe compensated for by the method of the present invention. As mentionedabove, the optical card carries information preferably related to atleast two fingers on each hand.

In the preferred embodiment, if there was not a positive match on thefirst fingerprint, another finger, preferably associated with the otherhand and chosen at random, is requested to be placed onto thefingerprint scanner. This finger is scanned by the fingerprint scannerand the same process, disclosed above, and as shown in FIG. 2, iscommenced until a decision is made either indicating a match or the lackthereof.

If in the second scan there is no match, a third finger is randomlyselected for scanning and measurement. If again there is no match withthe third randomly selected finger at 120, recognition of the individualcarrying the optical card could be denied at 125 or additional attemptsto verify identification could be pursued.

This method of allowing multiple attempts facilitates use of the card 25and verification of the identity of the individual, while the use ofhigher degrees of correlation assures that the security of accurateidentification is not sacrificed. Therefore, the system 20 for use inthe method of the invention preferably comprises a fingerprint scanner35 to scan one or more fingers in successive and sequential order; cardreader/writer 45 for receiving recorded fingerprint characteristicinformation from an optical card 25 inserted therein on the usercorresponding to the particular scanned finger(s); and a PU 37,connected to the fingerprint scanner 35 and card reader/writer 45, forcreating a coded signal representing the characteristics of the scannedfingerprint, extracting from the scanned fingerprint certain well knownindicators, and matching the recorded fingerprint characteristic datawith the scanned fingerprint extracted characteristics to establishidentity therebetween.

In addition to the fingerprint characteristics, the card can alsocontain other various biometric and representative information 28, 29,as shown, for example, in FIG. 5, about the individual card owner,inscribed on the card or electronically or optically stored, including,for example, the name, bank account number, date of birth, sex, height,weight, etc., and specifically, for a passport, the recorded media cancontain information on citizenship, health inspection and a completecatalog of travel history 130, all of which can be displayed at 129, 130on the PU 37 at any given location, as shown in the sample display 42 ofFIG. 3.

The present invention is useful in many applications. For example, agovernment may issue cards to be used by authorized recipients ofvarious government services, such as health insurance, welfare benefits,social security benefits, driver's licenses, or the like. The presentinvention can be used to prevent imposters from receiving such services.In this context, it should be noted that biometric data representingphysical characteristics of a plurality of persons, for example, afamily, can be stored on a single optical card whereby, for example, anymember of a family qualifying for government services can present thecard and be identified as a qualified recipient of such services.

In another embodiment of the present invention, the storage medium,rather than be portable, can exist at a fixed location along withstorage media storing biometric data for a number of other persons. Forexample, at secured facilities in which a limited number of people(e.g., employees) routinely request access, the storage medium can bebuilt into a main computer system as a series of secured memorylocations. In such a system, an employee, for example, seeking access tothe secured facility can have his identity verified without producing acard since the system can make the required comparison by requestingpresentation of appropriate employee body parts for scanning andcomparing biometric data extracted from the employee with biometric datarepresenting physical characteristics of relating to the employee storedin the secured memory location. The same successive and sequentialcomparison method as has been described above can then be used to permitor deny access.

While the preferred embodiment of the present invention has beendescribed, it should be appreciated that various modifications may bemade by those skilled in the art without departing from the spirit andscope of the present invention. Accordingly, reference should be made tothe claims that determine the scope of the invention.

I claim:
 1. An individual recognition system comprising:a storage mediumstoring as biometric data a plurality of physical characteristics of auser; reading means for extracting from the user biometric datarepresenting one of the physical characteristics stored by said storagemedium; comparison means for determining whether or not the extractedbiometric data represents the same physical characteristic ascorresponding stored biometric data obtained from said storage medium;and control means for instructing said reading means to extract from theuser additional biometric data representing a different physicalcharacteristic stored by said storage medium, depending on thedetermination by said comparison means.
 2. A system according to claim1, wherein the reading means includes a display for requesting that theuser present one of the user's body parts for extraction of thebiometric data corresponding thereto.
 3. A system according to claim 2,wherein the body part is one of the user's fingers.
 4. A systemaccording to claim 1, wherein the storage medium comprises a portablestorage medium.
 5. A system according to claim 4, wherein the portablestorage medium comprises an optical card.
 6. A system according to claim5, wherein said comparison means includes an optical card scanner.
 7. Asystem according to claim 1, wherein said comparison means outputs apositive comparison result if a match is found between the extractedbiometric data and the corresponding stored biometric data.
 8. A systemaccording to a claim 7, wherein the control means instructs said readingmeans to extract from the user additional biometric data if a positiveresult is not output by the comparison means.
 9. A system according toclaim 1, wherein said biometric data represents fingerprint data of aplurality of the user's fingers.
 10. A system according to claim 9,wherein said reading means comprises a fingerprint scanner.
 11. A systemaccording to claim 9, wherein in the comparison performed in saidcomparing means, the extracted biometric data corresponds to a randomlyselected first fingerprint of a user's hand, and if no match occurs upona scan of the first fingerprint, a second fingerprint from a randomlyselected other finger is selected by said control means.
 12. A systemaccording to claim 1, wherein said reading means comprises a retinalscanner.
 13. An individual recognition system comprising:a portablestorage medium storing as biometric data a plurality of physicalcharacteristics of a user; reading means for extracting from the userbiometric data representing one of the physical characteristics storedby said storage medium; comparison means for determining whether or notthe extracted biometric data represents the same physical characteristicas corresponding stored biometric data obtained from said storage mediumand outputting a positive comparison result if a match occurs; andcontrol means for instructing said reading means to extract from theuser additional biometric data representing a different physicalcharacteristic stored by said storage medium if said comparison meansdoes not output a positive test result.
 14. A system according to claim13, wherein the reading means includes a display for requesting that theuser present one of the user's body parts for extraction of thebiometric data corresponding thereto.
 15. A system according to claim14, wherein the body part is one of the user's fingers.
 16. A systemaccording to claim 13, wherein the portable storage medium comprises anoptical card.
 17. A system according to claim 16, wherein saidcomparison means includes an optical card scanner.
 18. A systemaccording to claim 17, wherein said biometric data representsfingerprint data of a plurality of the user's fingers.
 19. A systemaccording to claim 18, wherein said reading means comprises afingerprint scanner.
 20. A system according to claim 18, wherein in thecomparison performed in said comparing means, the extracted biometricdata corresponds to a randomly selected first fingerprint of a user'shand, and if no match occurs upon a scan of the first fingerprint, asecond fingerprint from a randomly selected other finger is selected bysaid control means.
 21. A system according to claim 13, wherein saidreading means comprises a retinal scanner.
 22. A personal identificationmethod using a data storage medium containing previously storedbiometric data representing a plurality of physical characteristics of auser, the method comprising:a first extracting step of extracting fromthe user biometric data representing one of the physical characteristicsstored by the storage medium; a determining step of determining whetheror not the extracted biometric data represents the same physicalcharacteristics as corresponding stored biometric data obtained from thestorage medium; and a second extracting step of extracting from the useradditional biometric data representing a different physicalcharacteristic stored in the storage medium depending on thedetermination at said determining step.
 23. A method according to claim22, wherein the first extracting step requests that the user present oneof the user's body parts for extraction of the biometric datacorresponding thereto.
 24. A method according to claim 23, wherein thebody part is one of the user's fingers.
 25. A method according to claim23, wherein the storage medium comprises a portable storage medium. 26.A method according to claim 25, wherein the portable storage mediumcomprises an optical card.
 27. A method according to claim 26, whereinsaid determining step is performed using an optical card scanner.
 28. Amethod according to claim 23, wherein the biometric data representsfingerprint data of a plurality of the user's fingers.
 29. A methodaccording to claim 28, wherein said first extract step uses afingerprint scanner.
 30. A method according to claim 28, wherein in saidfirst extracting step, the extracted biometric data corresponds to arandomly selected first fingerprint of a user's hand, and, if a matchdoes not occur in said determining step, a second fingerprint from arandomly selected other finger is selected for extraction at said secondextracting step.
 31. A method according to claim 23, wherein saiddetermining step outputs a positive comparison result if a match isfound between the extracted biometric data and the corresponding storedbiometric data.
 32. A method according to claim 31, wherein theadditional biometric data is extracted from the user if a positiveresult is not output at said determining step.
 33. A method according toclaim 23, wherein said first extraction step uses a retinal scanner. 34.A method for identifying one person from a plurality of persons, saidmethod comprising the steps of:gathering identification datarepresenting a plurality of physical characteristics from each of theplurality of persons; storing the gathered data; and providing apparatusfor repeatedly obtaining different identification data representingrespective ones of the plurality of physical characteristics from aperson presenting himself or herself and comparing obtainedidentification data with stored data until the obtained identificationdata matches stored identification data for the respective physicalcharacteristic.
 35. A method according to claim 34, wherein theidentification data repeatedly obtained at said providing step comprisesbiometric data corresponding to fingerprints of randomly selecteddifferent fingers of the person presenting himself or herself.
 36. Amethod according to claim 34, wherein the identification data gatheredat said gathering step comprises biometric data representingfingerprints of each of the plurality of persons and is stored on one ofa plurality of optical cards, and each of the plurality of optical cardsis issued to the person whose identifying data it contains, forpresentation by such person to establish his or her identity.
 37. Amethod according to claim 34, wherein said method is adapted todetermine which persons from a population of persons is a qualifiedperson, said method further comprising a step of analyzing the gatheredidentification data to verify whether or not each of the plurality ofpersons from whom data has been gathered is qualified.